The present invention relates to programming of mobile radiotelephones or the like, such as stations used in cellular service or personal communication service (PCS), to select systems using a carefully defined hierarchy of preferences but still allow the user certain options to select an available system even where the home and preferred systems may not be available. The invention also relates to a substantially one-rate type service, using stations implementing the system select feature.
Modern public wireless communication systems utilize a variety of cellluar and PCS technologies to offer customers mobility, specifically, the ability to make and receive telecom calls from anywhere that the wireless systems service. The networks or systems offering such services are becoming virtually ubiquitous. However, the systems are not homogenous. Different carriers operate different systems in different areas. In some cases, a station may operate with a large number of different systems, some of which may even implement different communications interfaces over the air-link.
Normally, a customer purchases service from a wireless carrier and obtains a mobile station compatible with the systems operated by that carrier. The carrier assigns the customer""s station to one of the systems that the carrier operates, as that customer""s xe2x80x9chomexe2x80x9d system. The station will often operate through that system, while the customer remains in the geographic area serviced by the home system. However, as the customer roams, the customer""s mobile wireless station must register with and operate through other public wireless systems, some of which are operated by the service provider and many of which are operated by other carriers.
Throughout much of the United States, multiple carriers offer competing wireless communication services in the same or overlapping areas. Some competing systems utilize different technologies, but in many areas there may actually be two or more systems offering service in a manner compatible with a customer""s station. Basic cellular service is divided into two bands, designated xe2x80x9cAxe2x80x9d and xe2x80x9cB.xe2x80x9d Typically, different carriers operate competing systems on the two bands. Originally, if a local landline telephone company operated a cellular system in their region, they were assigned to operate on the xe2x80x9cBxe2x80x9d band, and independent cellular providers were assigned to the xe2x80x9cAxe2x80x9d band. Over time, the systems and attendant air rights have changed hands, so that today, many major carriers operate A-side systems in some regions and B-side systems in other regions. Most cellular phones today actually are capable of operating on both bands. As the customer roams, the station therefore needs to select and register with an available system offering a compatible service on one or more of the bands of normal operation.
With many of the early cellular services, the customer set the mobile station to one of several modes, and once set, the mobile station performed a specific type of system selection defined by the mode until the customer changed the setting to a different mode. For example, the customer might set the station to operate with an assigned xe2x80x9chomexe2x80x9d system. In this mode, the station would operate with only the home system until the user changed the mode. If the station was out of range of the home system, the station did not operate but continually scanned to try to find and register with the home system.
Similarly, the user could set the station to the xe2x80x9cAxe2x80x9d side or to the xe2x80x9cBxe2x80x9d side. In either mode, the station would scan for a system on the particular band, but would not look for or select a system on the opposite band unless or until the user changed the selection mode setting. In many cases, the customer actually set the station to a selection mode to obtain service while roaming in one area but left the station in that setting when roaming to another area or even returning home. This often resulted in the station selecting a system that implemented less than favorable roaming charges. For example, if the home system was on the xe2x80x9cAxe2x80x9d side, the favorable roaming arrangements typically were with other systems operating of the same band. However, if the customer set the station to the xe2x80x9cBxe2x80x9d side, for example, to obtain roaming service in an area where there was no xe2x80x9cAxe2x80x9d side service, the station might remain in that mode. The station would continue to select more expensive xe2x80x9cBxe2x80x9d side systems even if an xe2x80x9cAxe2x80x9d side system became available, for example to the exclusion of even the home system.
Later mobile stations allowed the user to selected xe2x80x9cpreferredxe2x80x9d bands, typically A-preferred and B-preferred. In one of these modes, the station would first attempt to find a station on the preferred band and would scan the alternate band only if there was no system available on the preferred band. However, if the user set the station to the opposite preferred mode while roaming, the station would continue to operate in that mode, preferentially selecting the opposite-side systems over the home-side systems regardless of need or cost. Situations arose where an A-side agreement might be preferred in one area but a B-side roaming agreement might be more favorable in another area. For example, as carriers purchased different air-rights in different regions, the situation arose where a service provider might operate an A-side property in one region and operate one or more B-side properties in adjacent or surrounding regions. Selection of the service provider""s own systems would provide the optimum operation and financial arrangements for the subscriber and the service provider. However, the xe2x80x9cpreferredxe2x80x9d side selection techniques often result in selection of the unfavorable competing carriers"" services even if the provider itself has a system available to service the roaming subscriber. In the example, if the subscriber selects A-preferred while in the home region and roams to an adjacent region, if a competitor""s A-side system is available, the station selects the competing system even though the provider operates a B-side system in the adjacent area.
A number of automatic techniques have been developed and described in prior patents, to allow mobile telephone stations to more efficiently select service from available mobile telephone systems.
U.S. Pat. No. 5,586,338 to Lynch et al. teaches upgrading a cellular telephone system by modifying subscriber units for selective service provider acquisition during roaming. Priority of acquisition is given to those service providers associated with the home service provider. These preferred service providers are identified by System Identification (SIDs) numbers. A roaming subscriber unit will tune to control frequencies to identify all of the system providers operating in a physical area to which the subscriber has roamed. The subscriber station compares identified SIDs of the available systems to a list stored within the subscriber station. Selection is made based upon a priority of those system providers having arrangements with the home system provider.
U.S. Pat. No. 5,159,625 to Zicker teaches remote programming of system selection operations of a cellular mobile radiotelephone. More specifically, the programming causes the mobile telephone to select one of two or more frequency sets available for communication. The mobile telephone stores a list of system identification numbers (SIDs) that identify cellular systems for which cellular radiotelephone communication is to be prevented. In operation, the mobile telephone detects and displays when it is roaming. When roaming, the mobile telephone obtains a SID for the foreign cellular system upon which the telephone is currently configured to operate. The mobile telephone utilizes a first system selection process to select this foreign cellular system, which communicates on a first one of the sets of frequencies. The mobile telephone compares the SID of the foreign system to the stored list. If the default system""s SID is not on the list, operation continues normally. However, if the foreign system is identified as undesirable by the list of SIDs, the programming of the mobile telephone instructs the telephone to shift over to communicate on a different frequency set and select a system using an alternate system selection process. If a new system selected by the alternate process is not available or if a new system is available but listed on the SID list, then the mobile telephone simulates a xe2x80x98no servicexe2x80x99 mode of operation. However, if a new system selected by the alternate selection process is available and not identified as undesirable on the SID list, then the mobile telephone operates through the new system. After a predetermined duration of operation on the new system, the default selection process is restored to the first set of frequencies, and the procedure repeats.
U.S. Pat. No. 5,734,980 to Hooper, et al. discloses a technique for selecting the most preferred system among a number of available systems. A mobile terminal includes a random access memory, with a semi-permanent numeric access memory (NAM) for the mobile identification number (or xe2x80x9cMINxe2x80x9d) as well as the home system identification number (SID). The memory also stores a selection list of preferred systems. Each system identified on the list has an associated ranking, which identifies the degree of preference of the system relative to the other systems included on the list. To select a system for wireless communications, the mobile terminal scans a range of operating frequencies to detect wireless systems. Each time the terminal detects a wireless system, the terminal uses the list to determine whether the detected system is a most preferred system or a less preferred system. If the detected wireless system is most preferred, the terminal stops scanning and selects the detected wireless system for wireless communication. However, if the detected wireless system is a less preferred system, the terminal stores selection information for the system in a memory and continues scanning. Upon completion of the scanning, if the terminal does not detect a most preferred system, the terminal selects the highest-ranking system among the detected less preferred systems, for conducting its wireless communications.
U.S. Pat. No. 5,845,198 to Bamburak et al. discloses a system for searching for preferred providers, although if none are available, the station may register with less desirable systems. After power-up, the station clears a xe2x80x9cnon-optimalxe2x80x9d flag and then determines whether the last service provider used before power-down was an optimal service provider. This may be determined by checking the stored SID of the last service provider against a list of optimal and preferred service providers stored in memory. If the last service provider was optimal, the station attempts to lock onto the control signal of the last service provider. If the last provider was not optimal, or if the lock to the last provider is unsuccessful, then the station initiates a global spectrum search. If a lock is successful, the station determines whether the control channel contains the SID of an optimal service provider by comparing the SID from the control signal with the list of optimal service provider SIDs. If the SID does not belong to that of an optimal service provider, the global spectrum search is executed and the identity of the frequency band in which the non-optimal SID was located is passed to a global search routine, so as to avoid unnecessarily searching this portion of the spectrum again. However, if it is determined that an optimal service provider has been located, the station registers with that service provider. If an optimal service provider is not available, the station selects a preferred available system for registration and sets the non-optimal flag.
As described in the U.S. Pat. No. 5,845,198, when in an idle state, the control system of the station simply monitors the control channel of the service provider for communication system overhead information and for paging information that may indicate an incoming communication. While in idle state, a timer is activated which permits a low-duty cycle search if the phone is presently registered in a non-optimal service provider system. This situation may arise if the global spectrum search selects a preferred but not optimal service provider. Periodically, such as every 5 minutes, a step is executed to determine whether the non-optimal flag has been set, if the non-optimal flag is not set, the control system returns to its idle state. However, if the non-optimal has been set, the check thereof leads to the execution of the periodic search routine, where a search is conducted in order to attempt to locate an optimal service provider. If the periodic search routine identifies an available optimal service provider, the non-optimal service provider flag is cleared and the mobile communication device registers with the optimal service providers as a result of the periodic search routine.
U.S. Pat. No. 5,832,367 to Bamburak et al. discloses a communication device that locates a wireless service provider in a multi-service provider environment using a frequency band search schedule. The frequency band search schedule identifies a first or xe2x80x9chomexe2x80x9d band and a several other frequency bands in a predetermined order. The order of the frequency bands may be programmed by the user or by a home service provider over the air. The communication device searches for an acceptable service provider by examining the home band and then the other bands listed in the frequency band search schedule, in the order specified by the search schedule. An acceptable service provider is identified by comparing a service provider identifier received from a band being examined with a list of acceptable service providers.
In U.S. Pat. No. 5,903,832 to Seppanen, et al., a mobile station maintains a single, prioritized list of all available networks (i.e., all public, residential, and private networks). Access to the various networks is then based on the user""s needs. A first type of access is an automatic access, which requires little or no user involvement. A second type of access is to a user-specified network. A third type of access is to a user-specified service (e.g., data, fax, e-mail, etc.) that is supported by at least one of the networks. The mobile station can search for additional networks, and can also search for additional networks that support only a specified type of service, or for a network that supports a service not supported by networks that are already in the list. All of the networks can be searched at once so that the user can readily make a selection from the single, prioritized network list. The network priorities are user programmable by moving network names up and down in the list using a mobile station user interface, such as the mobile station""s keypad. The higher the network name is placed in the list, the higher is the selection priority of the network.
U.S. Pat. No. 5,870,674 to English suggests selecting a communication system in accord with geographic region of the subscriber station. The subscriber station first attempts to determine its geographic region, by attempting to acquire a system that covers the region. Once the subscriber station has determined its geographic region, the subscriber station then determines whether the acquired system is the most desirable system for use in the geographical region. If it is the most desirable system for use in the geographical region, the subscriber station registers with the acquired system. If it is not the most desirable system for use in the geographical region, the subscriber station attempts to acquire a more desirable system.
Other patents relating to SID list processing include the following:
U.S. Pat. No. 5,920,821 entitled xe2x80x9cUse of Cellular Digital Packet Data (CDPD) Communications to Convey System Identification List Data to Roaming Cellular Subscriber Stations.xe2x80x9d
U.S. Pat. No. 5,790,952 entitled xe2x80x9cBeacon System Using Cellular Digital Packet Data (CDPD) Communication for Roaming Cellular Stations.xe2x80x9d
U.S. Pat. No. 5,761,618 entitled xe2x80x9cUpdating Technique for Downloading New System Identification (SID) List Into a Handset.xe2x80x9d
U.S. Pat. No. 5,613,204 entitled xe2x80x9cBeacon System for Roaming Cellular Stations.xe2x80x9d
The prior system selection techniques, exemplified in the above-discussed patents have provided somewhat effective system selection, useful for certain types of services. However, there are still circumstances in which these system selection techniques do not adequately balance the communication needs of the customers with the financial aspects of certain roaming services.
For example, a number of providers are now offering a single-rate wireless telephone service, purportedly allowing customers to obtain mobile telephone service at the one-rate from anywhere within a large geographic area. Such providers implement the one-rate service by programming the customers"" stations with a list of identifiers for preferred systems, in a manner similar to several of the techniques disclosed in the cited patents. However, use of a system on the preferred list is absolutely mandatory. If a customer""s station can locate and operate through one of the preferred systems identified in the list, the customer can receive service at the one-rate. However, for the one-rate service, anytime that there is no available system identified in the list, the customer receives no service at all. The station indicates xe2x80x9cno servicexe2x80x9d and does not inform the user even though there may be alternate service available in the area.
With the ATandT one-rate service, for example, ATandT advertises that service is available anywhere in the United States. However, in several sections of the country, one of which is Asheville N.C., ATandT does not operate a system and does not have a preferential roaming agreement with a carrier serving that locale. ATandT customer stations therefore do not store identification data for any system at all, for that part of the country. Consequently, any ATandT customers roaming into such an area can not receive any service, not withstanding ATandT""s advertisement of nationwide service.
A need therefore exists for a technique to select wireless service systems, that steers traffic to systems implementing favorable billing arrangements with a one-rate service provider but does not deny service simply because a customer roams outside areas serviced by such systems. A need exists for such a system that allows the customer some other options to obtain service, whenever some compatible system is available. The service selection technique, however, should minimize reliance on less than favorable roaming arrangements based on the customer""s selections, to enable the provider to offer service on a one-rate plan or similar business structure. To the extent if any that a customer opts for a selection mode that may lock onto systems providing a least favorable financial arrangement, the station should automatically limit the financial exposure.
The present invention meets the above-stated needs and overcomes the problems with prior system selection techniques by providing user selectable modes of operation, which allow certain fall-back options when a preferred system may not be available, but still steers the bulk of the system selection operations to preferred systems. In a first mode, the mobile station scans for a broadcast system identifier or xe2x80x9cSIDxe2x80x9d that matches an identifier of a preferred system stored in memory of the handset. The stored identifier may be that of the home system or the stored identifier may be one from a group of stored identifiers, typically including the identifier of the home system and other preferred systems. The second mode allows the user at least one option, which involve selection of a less than preferred system, but with this mode, the mobile station will still make a first attempt to register with a system having a SID matching one stored in memory of the station. A preferred embodiment limits operation in at least one type of second mode, so as to revert to the first mode after occurrence of a predetermined event.
With this approach, the customer has a choice of service when outside of the service footprint of the carrier with whom the customer subscribes. However, whenever practical, the phone will stay on the most desirable system available, as directed by the customer""s carrier. If the user changes the system select mode to enable selection of a system not desirable by the carrier, in the preferred embodiment, the handset will automatically return to the more desirable system selection procedure even if the user forgets to manually change it back.
Thus, one aspect of the invention relates to a mobile communication station. The station includes a wireless transceiver for two-way communication via a selected one of a number of public wireless communication systems and for signaling with those systems. A programmable controller, coupled to the wireless transceiver, controls operation of the station including that of the transceiver. The station also includes a memory, for example, for storing one or more system identifiers. A user interface enables a user of the mobile station to provide a selection input to the programmable controller. The station also includes a program for execution by the programmable controller. The program execution causes the mobile station to operate in at least two modes in response to the selection input by the user. If a user selects a first mode, the programmable controller causes the transceiver to scan an air-interface only for a system identification matching an identifier stored in the memory and to register with a system broadcasting the matching system identification. However, if a user selects a second one of the modes, the station executes a hierarchical system selection procedure. The transceiver first scans the air-interface for a system identification matching an identifier stored in the memory of the mobile station, and if one is found, the transceiver registers with the system broadcasting the matching system identification. If the mobile station fails to detect a match for a stored identifier on the air interface, the transceiver performs an alternate scan of an air-interface to find an identifier for another system not identified in the memory of the mobile station. If the alternate scan detects an identifier of another system, the transceiver registers with that system.
In a preferred embodiment, the user interface comprises a display coupled to the programmable controller for displaying information including at least one mode selection option. The user interface also includes one or more keys coupled to the programmable controller for obtaining the selection input while the display shows the at least one mode selection option. The invention, however, encompasses other user interfaces, for example utilizing spoken command recognition and synthesized voice prompts.
The preferred embodiment actually implements four user selectable modes of operation. In a first of these modes, the transceiver scans the air-interface only for a system identification consisting of an identifier of a home system assigned to serve the mobile station and only locks onto or registers with a system broadcasting the home system identifier. In another mode utilizing stored identification, the memory stores a list of system identifiers for preferred public wireless communication systems, one of which may be that of the home system. In this mode the transceiver scans for and locks onto a system broadcasting an identification matching any one of the system identifiers contained in the list. The preferred roaming list of system identifiers may specify the system identifiers in a hierarchy of preference, e.g. based on best available cost.
The preferred embodiment implements two modes utilizing alternate scans, i.e. for systems not specifically matching stored identifiers. In one such mode, the transceiver scans for an available system on a band utilized by the station""s home system. In the other of these modes, the transceiver scans for an available system on a band different from that utilized by the station""s home system.
In the preferred embodiment, the system selection programming limits the operation in the alternate mode. This mode may be limited in duration or limited to one call for the station, particularly to one call through a system not identified in the station""s memory.
Other aspects of the invention relate to a methodology and a software product used in implementation of the method for controlling system selections by a mobile communication station. The methodology involves detecting a first user selection, and in response, operating in a first mode. The operations in the first mode include scanning an air-interface to detect a system identification, and locking onto a system broadcasting the detected identification only if that identification matches an identifier stored in memory of the mobile station. Upon detecting a second user selection, the method involves operating the station in another system selection mode. The operational steps in this second mode include scanning the air-interface first for a system identification matching an identifier stored in the memory of the mobile station and locking onto a system if the detected identification of that system matches a stored identifier. However, in the second mode, if there is no match to a stored identifier, the station performs an alternate scan of an air-interface and locks onto another system not identified in the memory of the mobile station.
The system selection techniques of the present inventions also enable a wireless service provider to offer service covering a wide geographic area using one-rate billing for all or at least most of the calls made by the one-rate subscribers. This aspect of invention involves establishing a home wireless communication system for providing wireless services for mobile stations of the subscribers at the one rate. The one-rate service provider also identifies foreign wireless communication systems that are xe2x80x9cpreferredxe2x80x9d systems. Typically, the preferred systems provide wireless services for mobile stations of the subscribers at a preferential rate, for example, at or near the cost of one-rate operation through the home system. Examples of such preferred systems include other systems operated by the service provider and systems operated by other providers that have contracted for preferential roaming charges with the one-rate service provider.
The one-rate service methodology involves storing system identifiers for the home system and the preferred systems in the mobile stations. The subscribers"" mobile stations are programmed to selectively operate in two system selection modes in response to user inputs. In the first mode, a mobile station scans an air-interface to detect a system identification. The station registers only with a system broadcasting a detected identification matching an identifier stored in the memory of the mobile station.
In the second system selection mode, the station first performs a scan and selection routine for selecting a system matching an identifier stored in memory. In this mode, however, this scan is not exclusive. Here, if there is no match to a stored identifier detected during scanning of the air interface, the station performs an alternate scan of an air-interface, and the station may lock onto another system not identified in the memory.
In accord with the one-rate billing methodology, the subscribers receive substantial services at the one-rate. Specifically, the service provider bills calls at only the one rate, at least for all calls through the home system and all calls through any of the preferred systems.
In preferred embodiments, the service provider may also bill at the one-rate for calls completed through certain types of other systems detected in the alternate scanning of the second mode, for example for systems operating on the same band as the home system. While the roaming agreements with other carriers on the home-band may not be as favorable as those offered by preferred systems, such agreements typically are relatively reasonable. The one-rate service provider often will be able to accept the slightly higher costs for services through such alternative systems as part of the cost of offering the popular one-rate service, because the system selection modes will still effectively steer the bulk of all traffic through the home system and the preferred systems.
However, if the alternate scan will likely involve still less favorable conditions, for example to systems on a band different than that used by the home system, then the preferred methodology places a limit on operation in any mode that may result in calls through systems found in the alternate scan. The mobile station will inform the user of the limit, for example by means of a display indicating a limit of five minutes or one call. The one-rate service provider may opt to bill for such calls, though the rate may not conform to the one-rate plan. In many cases, however, the user may need to make other billing/payment arrangements with the operator of the selected system, for example by arranging billing for each individual call to the user""s credit card account. Although single-rate billing may not be available in such a situation, the user can still obtain service.
Additional objects, advantages and novel features of the invention will be set forth in part in the description which follows, and in part will become apparent to those skilled in the art upon examination of the following or may be learned by practice of the invention. The objects and advantages of the invention may be realized and attained by means of the instrumentalities and combinations particularly pointed out in the appended claims.